The invention relates to a three function heat pump system. More particularly, the invention relates to a three function heat pump system for space heating, cooling and water heating, the system providing water heating all year long regardless of the system operating in the heating or cooling mode.
Systems for space heating and cooling are known. For example, U.S. Pat. Nos. 4,242,873; 4,270,518; 4,030,312; 4,242,872; 4,392,359; 4,302,942; 4,256,475; 4,246,956; 4,336,692; 4,279,359 and 4,011,731 disclose various systems for heat pumps which may provide for heating and cooling.
Nevertheless, the prior art systems fail to provide a system which is capable of hot water production all year long. The known systems only produce hot water when the system is operating in the heating or cooling mode using a desuperheater.
In addition, the components of the prior art systems are not arranged for efficient operation. For example, conventional systems have resistance crankcase heaters which operate continuously to warm the compressor so that liquid refrigerant does not migrate into the compressor during off-cycles. Crankcase heater operation has a negative energy impact, particularly in mild climates. Interconnection and assembly of the components of the prior art systems are also cumbersome and time consuming for installation in the field.
It is an object of the invention to obviate the disadvantages of the known systems by providing a three function heat pump system which generates domestic hot water all year long without requiring operation in a heating or cooling mode.
Another object of the invention is to provide a three function heat pump system which produces domestic hot water all year long by employing dual condensers that are connected in series or one at a time.
It is another object of the invention to provide a three function heat pump system having an arrangement of components which increases energy efficiency by eliminating the need for crankcase heaters.
It is a further object of the invention to provide a three function heat pump system which packages the components efficiently to conserve space and eliminate connections thereby facilitating rapid installation in the field.
An additional object of the invention is to provide a three function heat pump system which employs storage to facilitate heat pump operation under the most favorable available outdoor weather conditions.
These and other objects, advantages and features are provided by the three function heat pump system in accordance with the invention. The system includes a compressor for compressing the refrigerant into a high pressure, high temperature refrigerant. The refrigerant flows within a reversible flow conduit which provides series communication between a first heat exchanger located within a first reservoir and an external environment heat exchanger. A throttle means is located between the first heat exchanger and the external environment heat exchanger to reduce the pressure of the refrigerant. A reversing valve directs the refrigerant flow from the compressor through a second conduit to the reversible flow conduit, and selectively determines the direction of flow in the reversible flow conduit in response to a desired heating or cooling mode. In the heating mode, the reversing valve directs refrigerant flow in a first direction to the first heat exchanger to condense the refrigerant and transfer heat to a medium within a first storage reservoir prior to directing the condensed refrigerant through the throttle means to the external environment heat exchanger to evaporate the refrigerant. In the cooling mode, the reversing valve directs the refrigerant flow in a second opposite direction, first through the external environment heat exchanger to condense the refrigerant and then to the first heat exchanger to evaporate the refrigerant and absorb heat from the medium within the first reservoir.
The system provides hot water production irrespective of the heating and cooling modes by providing a second heat exchanger in a second hot water reservoir located between the compressor and the reversing valve. In addition, a bypass valve is provided for selectively bypassing the first heat exchanger. Accordingly, hot water is produced regardless of the heating and cooling modes by directing the refrigerant flow through the second heat exchanger to condense the refrigerant and then either directing the refrigerant to the first heat exchanger, or bypassing the first heat exchanger for direct flow to the external environment heat exchanger. With this arrangement, the second heat exchanger functions as a condenser for the system when the first heat exchanger is bypassed.